All practice pages/Interatomic theory/Elements
Element 46, a transition metal
A precious metal that soaks up hundreds of times its own volume of hydrogen, and the catalyst inside most gasoline car exhausts.
Period 5, group 10. The other transition metals are tinted, and every cell opens its own article.
Palladium has 46 electrons, one for every proton, so the atom carries no charge. Below are the same 46 electrons written two ways.
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰
Short form: [Kr] 4d¹⁰, where [Kr] stands for the 36 electrons krypton already has.
The simple form counts electrons shell by shell. The orbital form says which subshell each one sits in: s holds 2, p holds 6, d holds 10 and f holds 14. Shell 3 here is 3s² 3p⁶ 3d¹⁰, and 2 + 6 + 10 is 18.
Palladium sits in period 5, but its outermost shell is empty in the ground state, so the count stops at 4.
The outer shell holds 18 electrons. Those are the ones palladium can lose, gain or share, so they are the ones that decide what it bonds with.
Like other transition metals, palladium loses its outer s electrons, and often some d electrons as well, to form positive ions, and it can form more than one kind.
Mined with platinum and nickel, mostly at Norilsk in Russia and in South Africa.
William Hyde Wollaston isolated it from platinum ore in 1802 and, before announcing it, offered it anonymously for sale in a London shop in 1803 as new silver, which led other chemists to suspect a fraud. He named it after the asteroid Pallas, discovered in 1802.
Most goes into catalytic converters, especially for gasoline cars. It also goes into electronics, dental alloys, white gold jewelry and membranes that purify hydrogen. Palladium catalysts join carbon atoms together when making medicines, work recognized by the 2010 Nobel Prize in Chemistry.